Lamp tube



FIG. 1 is a perspective view of a lamp tube showing our new design;

FIG. 2 is a right side view of the lamp tube;

FIG. 3 is a rear view of the lamp tube;

FIG. 4 is a top view of the lamp tube;

FIG. 5 is a bottom view of the lamp tube;

FIG. 6 is a left side view of the lamp tube; and,

FIG. 7 is a front view of the lamp tube. 

CLAIM The ornamental design for a lamp tube, as shown and described. 